Improvement in electrical pressure-indicators



T. SHAW. Electrical Pressure Indicator.

No. 223,068. Patented Dec. 30, 1879.

WITNESSES: %JNVENTOR A TTORNE V N.PETF RS. PNOTO-LITHOGRAFHER.WASHINGTON D C UNITED STATES PATENT OFFICE.

THOMAS SHAW, OF PHILADELPHIA, PENNSYLVANIA.

IMPROVEMENT IN ELECTRICAL PRESSURE-INDICATORS.

Specification forming part of Letters Patent No. 223,068, dated December30, 1879; application filed November 15, 1879.

To all whom it man concern:

Be it known that I, THOMAS SHAW, of the city and county ot'Philadelphia,Pennsylvania, have invented a new and improved ElectricalPressure-Indicator for Attachment to Spring- Gages; and l hereby declarethe following to be a full, clear, and exact description of the same,reference being had to the accompanying drawings, and to the letters ofreference marked thereon.

My invention consists in the provision of short circuit-arms projectingfrom a bindingpost in front face of gage,and in the provision of shortcircuit-arms projecting from the axis or spindle of gage, operated inthe manner and for the purpose hereinafter explained.

The object of the invention is to give signal notice of any maximumpressure at which the gage may be set.

In order to enable others to use and practice my invention, I willproceed to describe its construction and operation.

()1) reference to the accompanying drawings, which form part of thisspecification, Figure 1 represents a face view of an ordinaryspring-gage, of which a is the hand or pointer of ordinary spring-gage,secured to the regular spindle in center of gage, and b is a shortmetallic arm secured to hand or spindle of gage; and Fig. 2, a detachedcentral section of the gage.

At the outer end of said arm b a metallic pin projects, to come incontact with metallic arms 0 and (1 whenever said arm bis moved on itsaxes far enough to touch the same.

The arms 0 and d are secured to the nut of a binding-post, 6, located inthe center of the glass front 0 of gage. The screw seeming the post toglass front passes through aperture in the glass.

The binding-post c, with its arms 00?, is insulated from all other partsof the gage, by reason of its support being upon the glass front 0. Awire, g, leads from one of the poles of an ordinary battery and connectswith said post 0.

The arm 12, secured to the hand and spindle of gage, is in metalliccontact with the metallic case of gage, and a binding-post, f, securedto any part of said case and connected with the other pole of thebattery, will place the gage in an electrical circuit, in which circuitis located an ordinary electrical bell, or other device that will givenotice whenever the current from battery is permitted to fiow.

The arm 0 is located to point at the desired minimum pressure, and thearm clat the desired maximum pressure.

It is the inlet to gage where it is connected to any source of pressure,and on the application of pressure to force the rotation of arm I), sothat the projecting pin on the end of same comes in contact with arm d,an unbroken electric circuit will be established that will ring bell,&c., of any striker device in said circuit, and thus give prominentnotice of the maximum pressure, and whenever said pressure is lowered,so as to permit pin on said arm I) to come in contact with arm 0, then asimilar notice will be given for the minimum pressure.

The arms 0 and d can be connected both with one post, 0, and the sameelectric hell, or can be connected, if desired, by separate posts andseparate bells; or one of said arms can be united when it is desired toalarm only at one point of pressure.

The ordinary glass front 0 of gage oifers a suitable. support for theinsulated post 0; but said post 0 might be located on other parts ofsaid gage with proper insulation without alteration in the result.

It will be evident that the same device without alteration answers forspring vacuumgagcs; but as vacuum-gages are actuated by air-pressure, Iclass this with pressure-gages.

hat I claim, and desire to secure by Letters Patent, is-

1. In spring pressuregages, the projecting arm I), connected withspindle of gage, in combination with insulated arms 0 and d, toestablish electric circuit with an electric hell or other mechanicaldevice actuated by the electric current.

2. In spring pressure-gages, the bindingpost 6, in combination with theglass front 0, the arms 0 and d, and arm I), substantially as and forthe purpose set forth.

THOMAS SHAW.

Witnesses WM. GARwooD, WM. B. HUGHES.

